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authorDmitry V. Levin <ldv@altlinux.org>2015-12-27 16:30:02 +0000
committerDmitry V. Levin <ldv@altlinux.org>2015-12-31 00:17:48 +0000
commite0043e17dfc52fe1702746543127cb4a87232bcd (patch)
tree73e7287e78b9775e8a4c603136fbf6c6fa1a5451 /sysdeps/unix/sysv/linux/tst-personality.c
parentcc42170ef6ca931c7527a86f14fc66059b6dfff4 (diff)
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Fix linux personality syscall wrapper
The personality system call, starting with linux kernel commit
v2.6.29-6609-g11d06b2a1e5658f448a308aa3beb97bacd64a940, always
successfully changes the personality if requested.  The syscall
wrapper, however, still can return an error in the following cases:
- the value returned by the system call looks like an error
due to architecture limitations of 32-bit kernels;
- a personality greater than 0xffffffff is passed to the system call,
and the 64-bit kernel does not have commit
v2.6.35-rc1-372-g485d527686850d68a0e9006dd9904f19f122485e
that would truncate this value to unsigned int;
- on sparc64, the value returned by the system call looks like an error
due to sparc64 kernel sign extension bug.

The solution is three-fold:
- move generic syscalls.list personality entry to generic 64-bit
syscalls.list file;
- for each 32-bit architecture that use negated errno semantics,
add a NOERRNO personality entry to their syscalls.list file;
- for sparc64 and 32-bit architectures that use dedicated registers
to flag syscall errors, add a wrapper around personality syscall;
if the system call return value is flagged as an error, this wrapper
returns the negated "would be errno" value, otherwise it returns
the system call return value; on sparc64, it also truncates the
personality argument to unsigned int before passing it to the kernel.

[BZ #19408]
* sysdeps/unix/sysv/linux/personality.c: New file.
* sysdeps/unix/sysv/linux/sparc/sparc64/personality.c: Likewise.
* sysdeps/unix/sysv/linux/tst-personality.c: Likewise.
* sysdeps/unix/sysv/linux/Makefile [$(subdir) == misc]
(sysdep_routines): Add personality.
(tests): Add tst-personality.
* sysdeps/unix/sysv/linux/syscalls.list (personality): Move ...
* sysdeps/unix/sysv/linux/wordsize-64/syscalls.list: ... here.
* sysdeps/unix/sysv/linux/arm/syscalls.list (personality): New entry.
* sysdeps/unix/sysv/linux/hppa/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/i386/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/m68k/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/microblaze/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/sh/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list (personality):
Likewise.
Diffstat (limited to 'sysdeps/unix/sysv/linux/tst-personality.c')
-rw-r--r--sysdeps/unix/sysv/linux/tst-personality.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/tst-personality.c b/sysdeps/unix/sysv/linux/tst-personality.c
new file mode 100644
index 0000000000..1bfa5029df
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-personality.c
@@ -0,0 +1,45 @@
+/* BZ #19408 linux personality syscall wrapper test.
+
+   Copyright (C) 2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <sys/personality.h>
+
+static int
+do_test (void)
+{
+  int rc = 0;
+  unsigned int test_persona = -EINVAL;
+  unsigned int saved_persona;
+
+  errno = 0xdefaced;
+  saved_persona = personality (0xffffffff);
+
+  if (personality (test_persona) != saved_persona ||
+      personality (0xffffffff) == -1 ||
+      personality (PER_LINUX) == -1 ||
+      personality (0xffffffff) != PER_LINUX ||
+      0xdefaced != errno)
+    rc = 1;
+
+  (void) personality (saved_persona);
+  return rc;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"